Method and system for recycling aluminum alloy rims using spectrographic analysis

ABSTRACT

A method and system of recycling aluminum alloy rims, the method and system comprising providing a feed of a plurality of aluminum alloy rims of different alloys, for each rim in the feed of aluminum alloy rims, determining a composition of that aluminum alloy rim, determining a plurality of recycled aluminum alloy composition ranges, and dividing the feed of aluminum alloy rims into a plurality of batches of aluminum alloy rims, each batch of aluminum alloy rims in the plurality of batches of aluminum alloy rims corresponding to an associated recycled aluminum alloy composition range in the plurality of recycled aluminum composition ranges, such that each rim in the plurality of aluminum alloy rims is allocated to an associated batch in the plurality of batches of aluminum alloy rims based on the composition of that aluminum alloy rim.

RELATED APPLICATIONS

This application claims priority from the U.S. Patent Application No.62/271,059, filed Dec. 22, 2015 entitled “METHOD AND SYSTEM FORRECYCLING ALUMINUM ALLOY RIMS USING SPECTROGRAPHIC ANALYSIS”, which isincorporated herein, in its entirety, by reference.

TECHNICAL FIELD

The embodiments disclosed herein relate to recycling processes and inparticular to methods and systems for recycling aluminium alloy rims.

INTRODUCTION

Aluminum has a relatively low density and high strength. Accordingly,aluminum by itself or alloyed with other metals is useful in manyapplications as it permits light weight constructions. For example,aluminum car rims can be made of high purity aluminum alloy, includingfrom Aluminum Association alloy number A356.2, as well as other alloys.Car rims may be anodized, coated with paint, clearcoat, chrome and/orother metal plating, and may contain components such as: lead weights,brass, rubber, brass fittings, stainless steel and iron inserts. If, forexample, a rim made from Aluminum Association alloy number A356.2 ismelted without removing these materials and components, then thecomposition of the melt may vary from the specification of alloy A356.2and the melt may not be suitable for use in casting new alloy wheelsmade from alloy A356.2. As a result, aluminum alloy wheels rims areoften recycled to produce less valuable products.

SUMMARY

A method of recycling aluminum alloy rims is disclosed. In oneimplementation, the method may comprise providing a feed of a pluralityof aluminum alloy rims from vehicles, and for each rim in the feed ofaluminum alloy rims, determining a composition of that aluminum alloyrim, determining a plurality of recycled aluminum alloy compositionranges, and dividing the feed of aluminum alloy rims into a plurality ofbatches of aluminum alloy rims, each batch of aluminum alloy rims in theplurality of batches of aluminum alloy rims corresponding to anassociated recycled aluminum alloy composition range in the plurality ofrecycled aluminum composition ranges. Each rim in the plurality ofaluminum alloy rims may be assigned or allocated to an associated batchin the plurality of batches of aluminum alloy rims based on thecomposition of that aluminum alloy rim.

In other implementations, the method may comprise, for each batch ofaluminum alloy rims in the plurality of aluminum alloy rims,determining, updating and storing batch-specific variables, wherein thebatch-specific variables comprise a batch-specific total weight ofaluminum alloy rims previously allocated to that batch, and abatch-specific average composition of aluminum alloy rims previouslyallocated to that batch. The batch-specific average composition ofaluminum alloy rims previously allocated to that batch may be calculatedbased on the weight and the composition of each aluminum alloy rimpreviously allocated to that batch. For each aluminum alloy rim, themethod may include allocating that aluminum alloy rim to the associatedbatch in the plurality of batches of aluminum alloy rims is based on, inaddition to the composition of that aluminum alloy rim and the weight ofthat aluminum alloy rim, the batch-specific total weight of aluminumalloy rims previously allocated to that batch and the batch-specificaverage composition of aluminum alloy rims previously allocated to thatbatch.

According to a further aspect, the determining the composition of eachaluminum alloy rim may be performed using a composition analyzer.Determining the composition may include exposing a portion of a baremetal surface of each aluminum alloy rim before determining thecomposition of that aluminum alloy rim, and determining a composition ofthe material from which the rim is made at that portion of the baremetal surface.

A system for recycling aluminum alloy rims is also disclosed. The systemmay comprise an aluminum alloy rim transfer mechanism for providing afeed of a plurality of aluminum alloy rims of different alloys to acomposition analyzer, for example a laser spectroscopy analyzer, fordetermining a composition of each rim. That is, the composition analyzermay be operable to determine the composition of each rim in theplurality of aluminum alloy rims. The transfer mechanism may include anysuitable (for the geometry and size of the rims to be recycled) one ormore of, or a combination of one or more of: a conveyor, apick-and-place unit, a robotic arm, and other relevant technologiesknown in the art. The composition analyzer may be positioned to receiveeach rim in the plurality of aluminum alloy rims from the aluminum alloyrim transfer mechanism.

Similar transfer mechanisms may be employed to transport the rims fromthe composition analyzer to other stations in the recycling process, andbetween the other stations (as will be described below) that may be partof the recycling process. The system may also include a computercomprising a non-transient memory and a processor in electroniccommunication with the non-transient memory, the non-transient memoryhaving stored thereon a plurality of recycled aluminum alloy compositionranges, the computer being in electronic communication with thecomposition analyzer to receive, for each rim in the plurality ofaluminum alloy rims, the composition of that rim, and the processorbeing operable to allocate each rim to a batch in a plurality of batchesof aluminum alloy rims based on the composition of that rim. Accordingto other embodiments, the system may include a weigh scale fordetermining a weight of each rim and may also include storingbatch-specific variables and carrying out one or more of theimplementations of the method of recycling aluminum alloy rims describedabove.

Other implementations and embodiments of the method and system forrecycling aluminum alloy rims will be described in the detaileddescription section below. Other aspects and features will becomeapparent, to those ordinarily skilled in the art, upon review of thefollowing description of some exemplary implementations and embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings included herewith are for illustrating various examples ofarticles, methods, and apparatuses of the present specification. In thedrawings:

FIG. 1 is a flow diagram illustrating one implementation of a method ofrecycling aluminum alloy rims;

FIG. 2 is a schematic illustrating a system for recycling aluminum alloyrims, according to one embodiment;

FIG. 3 is a flow diagram illustrating another implementation of themethod of recycling aluminum alloy rims.

DETAILED DESCRIPTION

Various embodiments of a method of recycling aluminum alloy rims andvarious embodiments of a system for recycling aluminum alloy rims willbe described below to provide examples of each claimed invention. Noembodiment described below limits any claimed invention and any claimedinvention may cover methods or systems that differ from those describedbelow. The claimed inventions are not limited to methods or systemshaving all of the features of any embodiment described below. It ispossible that a method, apparatus, process, or system described below isnot an embodiment of any claimed invention. Any invention disclosedbelow that is not claimed in this document may be the subject matter ofanother protective instrument, for example, a continuing patentapplication, and the applicants, inventors or owners do not intend toabandon, disclaim or dedicate to the public any such invention by itsdisclosure in this document.

Numerous specific details are set forth below in order to provide athorough understanding of the embodiments described herein. However, itwill be understood by those of ordinary skill in the art that theembodiments described herein may be practiced without these specificdetails. In other instances, well-known methods, procedures andcomponents have not been described in detail so as not to obscure theembodiments described herein. Furthermore, this description is notconsidered as limiting the scope of the embodiments described herein inany way, but rather as merely describing the implementation of theembodiments described herein.

FIG. 1 illustrates one implementation of a method 100 of recyclingaluminum alloy rims. The illustrated method may start with providing afeed 102 of a plurality of aluminum alloy rims of different alloys. Therims may be vehicle rims made from any aluminum alloy currently or inthe future used in the manufacture of rims for vehicles. The vehiclesmay be, for example, cars, trucks or motorcycles. It may be desirable todivide the feed 102 of aluminum alloy rims into one or more batches ofrecycled aluminum alloy, each batch having an average aluminum alloycomposition falling within a particular range of compositions.Accordingly, the method 100 may include determining a plurality ofrecycled aluminum alloy composition ranges that may be required at acertain point in time. For example, the method 100 may be used toproduce three batches of recycled aluminum. A recycled aluminum alloycomposition range may be determined for each batch.

In one example, one of the batches may be designated as a rejectionbatch for rims having an aluminum alloy composition falling outside ofthe composition ranges determined for the other batches or for rims thatare otherwise deemed to be unsuitable for recycling (see, for example,the discussion below relating to removing removable items from therims). In another example, the rejection batch may be designated forrims having an aluminum alloy composition that would take the averagecomposition of each of the other batches outside the desired compositionranges for those batches if the rims were added to those batches. Rimsassigned or allocated 112 to a rejection batch may be stored (forexample, see the optional storing step 314 a in the implementation ofthe method 300 illustrated in FIG. 3) and recycled at a later time andmay be recycled separately from the other batches of recycled aluminum,or may simply not be processed.

Each desired composition range may include limits for a plurality ofconstituents. Some limits may include a maximum limit and a minimumlimit. Other limits may include maximum limits only. For example, if abatch of recycled aluminum is assembled to make A356.2 aluminum alloyrims, then the composition range for that batch may include limitswithin which certain constituents of that batch, for example silicon andcopper, have to fit in order for the aluminum alloy of the rims madefrom that batch to qualify as A356.2 aluminum alloy. The limits may beexpressed in terms of minimum and maximum weight percent of total alloyweight. There may also be limits on other constituents, such asantimony, which are maximum limits. For example, it may be acceptable oradvantageous for a batch of recycled aluminum to contain zero or anegligible weight percent of antimony and unacceptable for the batch tocontain more than a specified maximum weight percent of antimony. Foreach batch and composition range associated with that batch, the limitsmay differ and may be dictated or chosen based on the purpose(s) forwhich that batch may be desired.

Determining and satisfying the composition ranges for each batch is aseparate issue from removing from each rim removable items such as steelbushings, lead balance weights, extra bolts, studs, coatings (forexample, clearcoat or paint), plating materials (for example, chromeplating or material used to anodize a rim), and valve stems. Suchremovable items may contain constituents for which there may be lowlimits in the desired composition ranges for each batch or constituentswhich may otherwise lower the quality of a batch of recycled aluminum.To avoid taking the average composition of an aluminum alloy batchoutside of a desired composition range for that batch and to avoidotherwise lowering the quality of that batch, the removable items mustbe removed. In some cases, depending on the purpose for which a batch ofrecycled aluminum may be desired, the desired composition range for thatbatch may allow for the removal of some but not all removable items, orfor the removal of a portion of each of the removable items, dependingon the nature of the particular removable items.

Thus, the method 100 may include dividing the feed 102 of aluminum alloyrims into a plurality of batches of aluminum alloy rims, each batch ofaluminum alloy rims in the plurality of batches of aluminum alloy rimscorresponding to an associated recycled aluminum alloy composition rangein the plurality of recycled aluminum composition ranges, such that eachrim in the plurality of aluminum alloy rims is assigned or allocated 112to an associated batch in the plurality of batches of aluminum alloyrims based on the composition of that aluminum alloy rim. That is, themethod 100 may include dividing the feed 102 by allocating each of therims to one of the batches of aluminum alloy rims (or, in some cases,batches of shreds of aluminum alloy rims, for implementations where therims may be shredded 110 prior to being allocated 112 to one of thebatches). In order to do this, the method 100 may include a compositionanalysis step 106. The composition of each of the aluminum alloy rimsmay be determined 106 by feeding that aluminum alloy rim to acomposition analyzer. In a preferred embodiment, the compositionanalyzer uses laser spectroscopy to determine in real time thecomposition of each rim.

In one example, the “Laser-Induced Breakdown Spectroscopy” (“LIBS”)composition analyzer manufactured by Laser Distance Spectrometry may beadapted as a composition analyzer suitable for the variousimplementations of the method 100. The LIBS composition analyzer mayinclude a radiation emitter, such as an Nd:YAG laser, and may focus aray of the Nd:YAG laser on one or more spots on a surface of each of therims passing in proximity to it at a manufacturer-specified speed anddistance. The laser may shine at a frequency ranging from 1 to 20 hertz,thereby raising the temperature of the rim material at the point(s) ofcontact between the rim material and the laser to above 30,000 degreesCelsius and generating plasma. The plasma may quickly cool down,returning the energized ions into a low energy state. While returning tothe low energy state, the ions may emit characteristic radiation. TheLIBS composition analyzer may contain one or more sensors that detectthe characteristic radiation. A processor may then analyze readingsobtained from the sensors and determine 106 from them the concentrationof the constituents contained in the material undergoing the temperaturechange. The processor may be disposed within the composition analyzer.Alternatively, the processor may be a remote processor.

The LIBS composition analyzer manufactured by Laser DistanceSpectrometry is designed for metallurgy, mining, coal and phosphateindustries. It is designed to provide analysis results that do notdepend on the quality of the surface of the analyzed material. Othersuitable composition analyzers may also have the capability ofperforming composition analysis irrespective of surface quality of thematerial to be analyzed. However, this feature may be undesirable in thecontext of recycling aluminum alloy rims. Some or all of the rims may beanodized with an anodizing material or have one or more coating orplating—for example, paint, clearcoat, or chrome. The Nd:YAG laser mayheat or burn such materials and this may contaminate the laserspectroscopy readings, potentially introducing errors into thecomposition readings. Heating or burning such coatings or platings mayalso produce emissions at least some of which may be toxic ordetrimental to the environment. Depending on the quantities of emissionsproduced if the composition analyzer is to be used as intended by themanufacturer, environmental equipment, such as bag houses or specializedfilters, as well as environmental permits, may be required. Complyingwith the resulting environmental, safety and legal requirements mayincrease the cost of recycling and in some cases may render therecycling commercially unfeasible.

In order to mitigate such complications and potentially reduceemissions, the recycling method 100 may comprise exposing 108 a portionof a bare metal surface of each aluminum alloy rim before determining106 the composition of that aluminum alloy rim at the portion of thebare metal surface. The steps of exposing the bare metal surface andanalyzing the composition of the material at the exposed bare metalsurface may be implemented in a number of ways, using any known suitabletechnology. Once the bare metal surface is exposed, the composition ofthe exposed material may be determined at the exposed bare metal surfaceby using a suitable composition analyzer, such as the LIBS compositionanalyzer described above.

Other suitable composition analyzers may include composition analyzersthat use laser spectroscopy or other system that relies on anothermethod of inducing characteristic radiation to be emitted by a materialof each rim at a surface of that rim and detecting and analyzing thatcharacteristic radiation to determine a composition 106 of thatmaterial. The composition analyzers may detect the characteristicradiation by using any suitable sensor—for example, suitable sensors mayinclude complementary metal-oxide-semiconductor (CMOS), high density,short channel metal-oxide-semiconductor (HMOS), charge-coupled device(CCD), and other types of sensors. For the purposes of theimplementations of the recycling method 100, it may be sufficient toassume that the composition of each rim throughout the rim is equal tothe composition of the rim material at the one or more spots tested bythe composition analyzer.

Suitable composition analyzers may use, for example, radiation emitterssuch as plasma, electron beam, or any other radiation emitters suitableto heat a material of each rim in at least one spot on a surface of thatrim to a point where the material will emit a sufficient quantity andquality of characteristic radiation while cooling down so as to permit asensor to detect that characteristic radiation and to allow for aprocessor to determine a composition 106 of the material from thatcharacteristic radiation. The composition analyzer(s) can be adapted towithstand continuous use, as well as typical conditions that may bepresent in a particular aluminum alloy rim recycling operation. Suchconditions may include vibrations resulting from the operation ofaluminum alloy rim transfer mechanisms, and dust and other particlesproduced in the recycling process. Exposing a portion of a bare metalsurface of each rim and determining the composition of the rim materialat that portion may produce fewer emissions. In a preferred embodiment,the operational speed of a suitable composition analyzer may match orexceed the speed(s) at which aluminum alloy rims may be fed to thecomposition analyzer.

The rims may be transported to a composition analyzer using a suitablealuminum alloy rim transfer mechanism. The position of a particular rimthe bare metal surface of which was exposed may be kept constantrelative to the transfer mechanism as the rim is transported to thecomposition analyzer. The bare metal spot may be exposed at a locationof the rim that can be subsequently aligned with, for example, the laserof the composition analyzer without repositioning the rim relative tothe transfer mechanism. For example, where the transfer mechanism is abelt conveyor, the position of a rim may be kept constant relative tothe conveyor belt.

In another example, a vision system in electronic communication with aservo positioning system may be used. The vision system may track theposition of each rim and the location of the exposed portion of the baremetal surface of each rim by analyzing a top surface of each rim andmeasuring the coordinates of the exposed portion of the bare metalsurface relative to a pre-determined reference point. The vision systemmay communicate the coordinates to the servo positioning system once therim is transported to the composition analyzer and the servo positioningsystem may position the rim so as to present the exposed portion of thebare metal surface to the composition analyzer. The servo positioningsystem may include any combination of known servo-motors andcontroller(s) suitable for the geometry, size, and weight of the rims tobe recycled. Suitable manufacturers of servo positioning systems mayinclude: AB, Yaskawa, and Mitsubishi.

Similar transfer mechanisms may be employed to transport the rims fromthe composition analyzer station to other stations in the recyclingprocess, and between the other stations that may be part of therecycling process. The position of each rim or of the exposed portion ofthe bare metal surface may or may not need to be tracked while the rimis transported after the composition analysis step. For example, theremay no longer be a need to track the position of the exposed portion ofthe bare metal surface of a rim after the rim passes the compositionanalysis step. On the other hand, the position of the rim may need to betracked when transporting the rim to and between the other stations thatmay be part of the recycling process. For example, tracking rim positionmay be required in order to stage parallel upstream processing lines120, 150 in order to optimize the performance of a shredder into whichthe lines may converge. Parallel upstream processing 120, 150,shredding, and optimization will be described below.

As mentioned above, determining the composition 106 of each rim at theexposed portion of the bare metal surface may reduce the emissions thatmay otherwise be produced at the composition analysis step 106. Anotherbenefit of this step may be that the composition of each of the rims maybe determined 106 more accurately and in some cases false determinationsmay be avoided. False determinations may lead to aluminum alloy rimsthat are suitable for higher value batches being allocated 112 to lowervalue batches, or perhaps even being allocated 112 to a rejection batch.

In the example of a LIBS composition analyzer, an inaccurate compositionreading or a false determination may occur where, for a particular rim,depending on the thickness and the type of coating or plating materialthat may be present on the rim, the Nd:YAG laser may not penetrate ormay insufficiently penetrate the coating or plating material. In somecases, a false determination of the material of which a particular rimmay be made may result in that rim being added to a wrong batch, therebycausing the average composition of that batch to fall outside of thedesired range of compositions for that batch.

By removing any coating or plating, or a substantial portion of thecoating or plating, at the spot(s) to be tested by the compositionanalyzer, the likelihood of the occurrence of false determinations maybe reduced and the accuracy of at least some of the composition readingsmay be improved. In some embodiments, the composition analyzer may becapable of removing the required amount of coating or plating using itsradiation emitter; however, for the reasons stated above, using, forexample a laser, for this purpose may not be desirable. In a preferredembodiment, the bare metal surface may be exposed by using one or moresuitable mechanical devices.

For example, suitable mechanical devices may include one or more of: adrill, a burr, or an end mill. In a system, the step of exposing 108 aportion of a bare metal surface of each aluminum alloy rim may beimplemented as a manual or as an automated step, or as a combination ofmanual and automated steps. Any suitable combination of known technologyand controllers may be used to implement this step in an automatedmanner. For example, the rims may be transported to a station where therims pass by an automatic cutting tool, such as an end mill, whichremoves an amount of surface material from a spot on each of the rims soas to create an exposed bare metal surface on each of the rims.

In some cases, it may be desirable for the method 100 to furthercomprise, for at least one rim in the plurality of aluminum alloy rims,or for each rim in the plurality of aluminum alloy rims, determining aweight (i.e. weighing) 114 of that aluminum alloy rim. In these cases,dividing the feed of aluminum alloy rims into the plurality of batchesof aluminum alloy rims may comprise, for that aluminum alloy rim,allocating 112 that aluminum alloy rim to the associated batch in theplurality of batches of aluminum alloy rims based on both thecomposition of that aluminum alloy rim and the weight of that aluminumalloy rim. These steps may allow, for each batch of aluminum alloy rimsin the plurality of aluminum alloy rims, determining, updating andstoring batch-specific variables.

For each batch, the batch-specific variables may comprise abatch-specific total weight of aluminum alloy rims previously allocated112 to that batch, and a batch-specific average composition of aluminumalloy rims previously allocated 112 to that batch. The batch-specificaverage composition of aluminum alloy rims previously allocated 112 tothat batch may be calculated based on the weight and the composition ofeach aluminum alloy rim previously allocated 112 to that batch. In someembodiments, for example as shown 320 in the implementation of themethod 300 in FIG. 3, weighing 114 each aluminum alloy rim may becontemporaneous, or slightly before or after determining 106 acomposition of that rim 106. Each rim may be individually weighed 114.

In some example implementations of method 100, for each aluminum alloyrim, allocating 112 that aluminum alloy rim to the associated batch inthe plurality of batches of aluminum alloy rims can be based on, inaddition to the composition of that aluminum alloy rim and the weight ofthat aluminum alloy rim, the batch-specific total weight of aluminumalloy rims previously allocated 112 to that batch and the batch-specificaverage composition of aluminum alloy rims previously allocated 112 tothat batch. These steps may allow for more accurately calculating,keeping track of, and controlling the batch-specific average compositionand the batch-specific total weight of each of the batches of recycledaluminum. These steps may also increase the efficiency of the recyclingmethod 100. The feed 102 of aluminum alloy rims may include rims havinga composition that falls outside each of the recycled aluminum alloycomposition ranges.

The comparison of the weight and composition of each rim with thebatch-specific total weight and the batch-specific average compositionof each batch and the required composition range for each of the batchesmay show that a particular rim would not take the average composition ofat least one of the batches outside of the required composition range ofthat batch. It this case, that rim may be allocated 112 to one of the atleast one of these batches. The comparison may also show that that therim would take the average composition of any one of the batches outsideof the required composition range of that batch, or unacceptably closeto the boundary of the composition range. In that case, the rim may beallocated 112 to a rejection batch. A system, for example the system 200illustrated in FIG. 2, may allocate 112 the rims automatically.Non-aluminum or otherwise unsuitable rims may be allocated to arejection batch automatically or manually, depending on the particularrecycling operation.

One or more of the aluminum alloy rims in the feed 102 may have one ormore removable items. The removable items may include any one or more ofsteel bushings, lead balance weights, extra bolts, studs, coatings (forexample, clearcoat or paint), plating materials (for example, chromeplating or material used to anodize a rim), and valve stems. Thepresence of the removable items in the recycling process may beundesirable in that it may reduce the purity of a resulting recycledaluminum alloy batch and in some cases may take the average compositionof that batch outside of the recycled aluminum alloy composition rangerequired for that batch. Also, as described below, one or more shreddersmay be used in the recycling process. Depending on the type ofshredder(s) used, some types of removable items, such as steel bushingsor other steel items, may damage the shredder(s). Accordingly, dependingon the particular removable items present on a particular rim, it may bedesirable to remove 118 some, portions of, or all of the removableitems. Depending on the type of shredder(s) and if such items, orportions of such items, cannot be removed from a particular rim, it maybe necessary to reject that rim from the recycling process.

Thus, the method 100 may include locating 116 and removing 118 removableitems steps. One or both of these steps may be performed manually orautomatically, or in a combination of manual and automatic steps,depending on the particular recycling operation. The rim may be rejectedby manually taking it out of the feed of aluminum alloy rims 102 or byallocating 112 it to a rejection batch. The rim may also be rejectedmanually after visual inspection of the rim after the removal ofremovable items step 118, or automatically after automated verificationof whether the removable items that were located were removed. In orderto automate at least one of these steps, the rims may be fed to ameasurement system which may determine the number, if any, of theremovable items on each of the rims 116. The measurement system may alsodetermine the coordinates 116 of each of the removable items, relativeto, for example, a reference point on the corresponding rim or relativeto a reference point on the aluminum alloy rim transfer mechanism bywhich the corresponding rim may be transported. In a system, this stepmay be automated using any suitable combination of known technology andcontrollers. For example, a laser measurement system in combination withan indexing conveyor, a walking beam transfer, a robot, or apick-and-place unit can be used.

Accordingly, method 100 for recycling aluminum alloy rims illustrated inFIG. 1 in accordance with an aspect of an embodiment of the presentinvention, comprises providing a feed 102 of aluminum alloy rims andlocating 116 the removable items, if any, on each of the rims in thefeed 102. As shown, the locating step 116 may include determining thenumber of and the coordinates of the removable items, if any, on each ofthe rims and may be implemented using a suitable measurement system. Asshown, locating 116 removable items may be followed by removing 118 atleast some of or at least portions of the removable items from each ofthe rims. In a particular example, removal 118 of removable itemsincludes an automated bushings press-out. Bushings press-out may beachieved by any suitable system. The suitable system may include one ormore of or a combination of, for example, a multi-axes servo drivenpress operating automatically based on the coordinates of the bushingsdetermined at the measurement step 116, a dedicated press havinginterchangeable sets of press-out tools for particular types ofbushings, and a rotary table in combination with single axis press.

After the removal of removable items 118, each of the rims may bevisually inspected to confirm that the removable items have been removed118. An inspector may then decide, for each rim, whether to take the rimout of the recycling process, or to direct the rim for furtherprocessing. Alternatively, the visual inspection step may be automatedby, for example, recirculating each of the rims to the measurementsystem. In this case, for each rim, once the measurement system locates116 any remaining removable items on that rim, a processor may comparethe remaining removable items data to the data for that rim obtainedbefore the removal of removable items 118 and may generate a controlsignal to either direct the rim for further processing or to allocate112 the rim to a rejection batch. Where a rim is directed for furtherprocessing, the method 100 may proceed to a step of determining acomposition 106 of that rim. Preferably, the method 100 includesexposing a portion of a bare metal surface 108 of each rim prior todetermining the composition 106 of that rim at that portion of the baremetal surface.

The method 100 may further include shredding 110 the rims in the feed102 of aluminum alloy rims. In some implementations of the method 100,the rims may be shredded 110 before being allocated 112 to one of thebatches. In other implementations of the method 100, the rims may beshredded 110 after being allocated 112 to one of the batches and may ormay not be shredded if allocated 112 to a rejection batch, depending onthe requirements of the particular recycling operation and theconfiguration of the system performing the method 100. In a preferredimplementation of the method 100, the shredding step 110 is performeddownstream from the determining composition 106 and the weighing 114steps, as it is simpler, in many cases, to determine the composition ofan intact rim, as opposed to the shredded pieces of a rim. In theimplementation shown in FIG. 1, the shredding step 110 takes place afterthe weighing step 114. In these embodiments, there may be no need tocontinue distinguishing the shreds of one rim from the shreds of anotherrim provided they have all been allocated 112 to the same batch.

Any suitable shredder known in the art may be used. For example,aluminum alloy car rims may be supplied to a hopper of a conventionalshredding apparatus, such as the SSI Series 45H shredder available fromSSI Shredding Systems Inc. at 9760 SW Freeman Drive, Wilsonville, Oreg.,97070-9286, USA. This shredding apparatus may include a cutter boxhousing the cutters, which can be mounted on parallel shafts that rotatehorizontally in opposite directions. The feed hopper can be locatedabove the cutter box. Due to the force of gravity, the rims placed inthe feed hopper can then be fed downwardly into the proper locationwhere they can be engaged by the cutters and torn or cut into shreds.Preferably, the rims are cut or torn into shreds of two to three inchesin length and, more preferably, approximately two inches in length.

In a preferred implementation of the method 100, the shredder isswitchable between serving the different batches or paths of travel thatmay be provided for one or more of the batches. For example, theshredder may be first selected to shred the rims allocated 112 to one ofthe batches, and may subsequently be switched to shredding 110 the rimsallocated 112 to another one of the batches, depending on theavailability of rims in the feed 102 and the demand(s) for differentcompositions of recycled aluminum that may exist at the time. When therims are shredded 110, at least portions of the removable items such asvalve stems may be freed up such that a percentage of these may beremoved from the recycling process by a magnetic separator and,optionally, an eddy current separator.

The shredding 110 may also produce fines and dirt. Preferably, thesebyproducts may be separated from the shreds by method steps such asscreening. For example, the shreds may be fed to a vibrating screen. Thefines and dirt may pass through the vibrating screen and may bepreferably recovered by melting or an alternative process. The shreddedpieces may need to be further cleaned, for example, by shot blasting.The steps of screening, recovery of fines and dirt, magnetic and eddycurrent separation, and shot blasting are known in the art may beimplemented as described in the prior art. For example, these steps andthe apparatuses corresponding to these steps may be implemented asdescribed in U.S. Pat. No. 6,983,901. These steps may be referred tocollectively as downstream processing. The steps that may be performedprior to the shredding step 110 may be referred to as upstreamprocessing. It will be appreciated that a step may in one implementationof the method 100 be part of upstream processing and may be part ofdownstream processing in another implementation of the method 100.

In some embodiments, depending on the kind and capacity of theshredder(s) being used, shredding 110 may be able to occur at a muchhigher rate than the upstream processing steps 150 of locating removableitems 116, removing removable items 118, determining 106 a compositionof the rim (including exposing up portion of bare metal surface 108according to some embodiments) and weighing the rim 114. In theseembodiments, multiple lines may be provided upstream of shredding 110for parallel upstream processing 120 to sort rims into differentbatches. The upstream processing lines may be staged to not interferewith each other and the shredder can then be switched between shreddingfor the different batches. By using parallel upstream processing 120,the combined upstream processing rate can be increased to match, or atleast be closer to, the processing rate of the shredder.

FIG. 2 illustrates an embodiment of a system 200 for recycling aluminumalloy rims. The system 200 comprises an aluminum alloy rim conveyor 202for providing a feed of a plurality of aluminum alloy rims of differentalloys and a composition analyzer that is a laser spectroscopy analyzer204 for analyzing and thereby determining the composition of each rim inthe plurality of aluminum alloy rims. The laser spectroscopy analyzer204 is operable to determine 106 a composition of each rim in theplurality of aluminum alloy rims and is positioned to receive each rimin the plurality of aluminum alloy rims from the aluminum alloy rimconveyor 202. The system 200 further comprises a computer 206 inelectronic communication 208 with the laser spectroscopy analyzer 204 toreceive, for each rim in the plurality of aluminum alloy rims, thecomposition of that rim. The computer 206 comprises a non-transientmemory 206 a and a processor 206 b in electronic communication 206 cwith the non-transient memory 206 a. The non-transient memory 206 a hasstored thereon a plurality of recycled aluminum alloy compositionranges. The processor 206 b is operable to allocate 112 each of the rimsto a batch in a plurality of batches of aluminum alloy rims based on thecomposition of that rim.

As shown, a weigh scale 210 may be disposed downstream of the laserspectroscopy analyzer 204 and may receive each of the rims from theconveyor 202. The weigh scale 210 may be in electronic communication 208with the computer 206. The weigh scale 210 may be operable to determinea weight 114 of each rim in the plurality of aluminum alloy rims. Theprocessor 206 b may be operable to allocate 112 each rim to a batch inthe plurality of batches of aluminum alloy rims based on both the weightand the composition of that rim. For each batch in the plurality ofbatches of aluminum alloy rims, the system 200 may store in thenon-transient memory 206 a of the computer 206 a plurality ofbatch-specific variables. The batch-specific variables may comprise abatch-specific total weight of aluminum alloy rims previously allocated112 to that batch, and a batch-specific average composition of aluminumalloy rims previously allocated 112 to that batch.

The batch-specific total weight of aluminum alloy rims previouslyallocated 112 to that batch may be calculated based on the sum of theweights of each aluminum alloy rim previously allocated 112 to thatbatch. The batch-specific average composition of aluminum alloy rimspreviously allocated 112 to that batch may be calculated based on theweight and the composition of each aluminum alloy rim previouslyallocated 112 to that batch. For each aluminum alloy rim, the system 200may allocate 112 that aluminum alloy rim to the associated batch in theplurality of batches of aluminum alloy rims based on, in addition to thecomposition of that aluminum alloy rim and the weight of that aluminumalloy rim, the batch-specific total weight of aluminum alloy rimspreviously allocated 112 to that batch and the batch-specific averagecomposition of aluminum alloy rims previously allocated 112 to thatbatch.

As shown, the system 200 further comprises a diverter 216 and aplurality of paths of travel 212 a, 212 b, 212 c, . . . , 212 n for thefeed of the plurality of aluminum alloy rims downstream from the laserspectroscopy analyzer 204, and a plurality of storage spaces 214 a, 214b, . . . , 214 n downstream of the diverter 216. The system 200 mayallocate 112 each of the rims to one of the batches by diverting andtransporting each rim in the plurality of aluminum alloy rims along apath of travel 212 a-212 n selected out of the plurality of the paths oftravel 212 a-212 n. In other words, the system 200 may transport eachrim in the plurality of aluminum alloy rims along a selected path oftravel 212 a-212 n in the plurality of paths of travel 212 a-212 n basedon the batch in the plurality of batches of aluminum alloy rims selectedby the processor 206 b for that rim. This logic may be implemented, forexample, as follows. The laser spectroscopy analyzer 204 may determinethe composition 106 of each of the rims in the feed 102 and may, foreach of the rims, transmit the reading for that rim to the computer 206.

The computer 206 may compare the reading and the weight of the rim tothe aluminum alloy composition ranges and the batch-specific totalweight and the batch-specific average composition of each batch, maycalculate whether the rim may be allocated 112 to one or more than oneof the batches without taking the average composition of that batch (orbatches) outside of the composition range desired for that batch (orbatches), and may produce a control signal reflecting the result of thiscalculation. The computer 206 may then allocate 112 the rim by sendingthe control signal to the diverter 216. In implementations of the methodthat do not involve batch-specific variables, the computer 206 maysimply compare the composition reading of each rim with the requiredaluminum alloy composition range of each of the batches. If the readingis outside of each of the ranges, the computer 206 may produce and senda signal to the diverter 216 to allocate 112 the rim to a rejectionbatch, if one is designated. Depending on the particular recyclingoperation, the system 200 may include more than one diverter 216.

Alternatively, the computer 206 may also divert the rim out of therecycling process, even if the allocation 112 of that rim to one of thebatches would not take the average composition of that batch outside ofthe aluminum alloy composition range required for that batch. Forexample, a rim that is exceptionally pure may be diverted out of therecycling process so that the computer 206 or an operator cansubsequently make a decision about where to allocate 112 that rim.Alternatively, a rim that could be allocated 112 to one of the batcheswithout taking the average composition of that batch outside of thealuminum alloy composition range required for that batch, but whichwould bring the average composition of that batch unacceptably close tothe boundary of the aluminum alloy composition range required for thatbatch, might be diverted out of the recycling process, so that adecision of whether or not to allocate 112 that rim could be delayeduntil more information is available, as the batch is closer tocompletion, about whether that rim can be safely allocated 112 to thatbatch.

Where an aluminum alloy rim is of exceptional purity such that it can beallocated 112 to more than one of the batches, it may be, in some cases,advantageous to allocate 112 that aluminum alloy rim to the highestvalue alloy batch. In other cases, it may be more advantageous toallocate 112 that aluminum alloy rim to a particular batch having abatch-specific average composition that is close to a boundary of thecomposition range required for that batch. In this way, that batch canbe made more pure, such that potentially allocating 112 a fewexceptionally pure rims to that batch can preserve or increase the valueof that entire batch.

As shown in FIG. 2, each storage space 214 a-214 n in the plurality ofstorage spaces 214 a-214 n may be part of a different path of travel 212a-212 n in the plurality of paths of travel 212 a-212 n. As shown by thepath of travel 212 a, one or more of the paths of travel 212 a-212 n mayhave no storage space associated with the one or more paths of travel212 a-212 n. Each of the paths of travel 212 a-212 n may include aconveyor operable independently of the conveyors associated with theother paths of travel 212 a-212 n. A shredder 218 may be disposeddownstream of the diverter 216 and the paths of travel 212 a-212 n mayconverge into the shredder 218. Downstream processing stations 220 maybe disposed downstream of the shredder 218 and may include shotblasting, magnetic and eddy current separation steps. As noted above,these steps may be implemented for example as described in U.S. Pat. No.6,983,901.

Depending on the particular recycling operation, the system 200 mayinclude multiple shredders 218. A shredder 218 may be one of the moreexpensive components of the recycling system 200. Accordingly, it may bedesirable to minimize the quantity of shredders 218 used in therecycling process while maximizing the output of the recycling process.As shown in FIG. 2, the system 200 includes one shredder 218. The speedat which the shredder 218 may shred each rim may exceed the speed ofupstream processing. In such cases, the recycling method may include oneor more parallel upstream processing lines 220. For example, where theshredder 218 may shred 110 each of the rims twice as quickly as each ofthe rims may be processed upstream 150, the provision of two upstreamprocessing lines 220 in parallel may allow to utilize the shredder 218at or close to its shredding capacity and thus maximize the utility ofthe shredder 218 and the output of the recycling process.

In cases where the system 200 is implemented with parallel upstreamprocessing 220, the computer 206 may be programmed to stage the upstreamprocessing 220 in order to ensure that the outputs from the upstreamprocessing lines 220 do not interfere with each other and to ensure thateach of the rims may be individually allocated 112 to one of the batchesso as to avoid incorrect allocations. In these implementations, asmentioned above, the position of each of the rims may be tracked tofacilitate the staging. It will be appreciated that this staging may beimplemented using any suitable program code and hardware by a personskilled in the art without the use of inventive ingenuity but based onthe logic described in this document.

Particular requirements of the staging, such as particular shreddingspeeds, delays, sensing steps monitoring when one stage or a combinationof stages of the method 100 are completed, may be dictated by theparticular combination of components used in the system 200, and bytheir operating characteristics (such as speed). In some cases, thesystem 200 may be further optimized by minimizing the number ofcomponents carrying out the recycling method 100. For example, dependingon the characteristics of the particular components used in the system200, it may be possible to use a single weigh scale 210 between twoupstream processing lines 220 without decreasing the overall output ofthe processing lines 220.

FIG. 3 illustrates another implementation of the method 300 forrecycling aluminum alloy rims. The method 300 may comprise upstreamprocessing 320 and downstream processing 322 steps and variations ofimplementations of those steps 320, 322 that are analogous to thosedescribed in relation to the method 100. Also, cheaper but slowershredders may be or may become available. Thus, depending on theparticular aluminum alloy rim recycling operation, it may be or maybecome advantageous to use a plurality of such shredders. As shown, themethod 300 includes shredding 318 the rims in a plurality of parallelshredding steps 318, which may be collectively referred to as a parallelshredding step 318, in which a plurality of shredders may be used, withappropriate staging.

It will be appreciated that depending on the number and the speed ofshredders, it may be advantageous or necessary for the method 300 toinclude storing 314 a, 314 b the one or more of the batches in one ormore storage spaces 214 a, 214 b, . . . , 214 n prior to sending themfor shredding 318. Storage requirements and storage times may bedictated by the availability of and the particular compositions ofavailable rims of different aluminum alloys, as well as the demand(s)for recycled aluminum batches having particular compositions that may beoccurring at those particular times. Similar considerations may apply totemporarily storing the shreds in one or more of the batches after theshredding step 318. Temporarily storing 314 a, 314 b one or more of thebatches may provide a more optimal operation of the method 300 and mayfacilitate matching, for any given point in time, the supply of rims inthe feed 302 with one or more demands for recycled aluminum occurring atthat point in time.

While the above description provides examples of one or more apparatus,methods, or systems, it will be appreciated that other apparatus,methods, or systems may be within the scope of the claims as interpretedby one of skill in the art.

The invention claimed is:
 1. A method of recycling aluminum alloy rims,the method comprising: providing a feed of a plurality of aluminum alloyrims of different alloys; for each rim in the feed of aluminum alloyrims, determining a composition of that aluminum alloy rim; determininga plurality of recycled aluminum alloy composition ranges; and dividingthe feed of aluminum alloy rims into a plurality of batches of aluminumalloy rims, each batch of aluminum alloy rims in the plurality ofbatches of aluminum alloy rims corresponding to an associated recycledaluminum alloy composition range in the plurality of recycled aluminumcomposition ranges, such that each rim in the plurality of aluminumalloy rims is allocated to an associated batch in the plurality ofbatches of aluminum alloy rims based on the composition of that aluminumalloy rim, where determining the composition of each aluminum alloy rimis performed by heating a material of that rim in at least one spot on asurface of the rim to a point where the material will emit acharacteristic radiation while cooling down, using a sensor to detectthat characteristic radiation, and using a processor to analyze thatcharacteristic radiation to determine the composition of the material.2. The method of recycling aluminum alloy rims as defined in claim 1,wherein the heating is performed by focusing a ray of a laser on the atleast one spot on the surface of that rim.
 3. The method of recyclingaluminum alloy rims as defined in claim 1, further comprising exposing aportion of a bare metal surface of the aluminum alloy rim beforedetermining the composition of each aluminum alloy rim and wherein theat least one spot on the surface of the rim is located at that portionof the bare metal surface.
 4. The method of recycling aluminum alloyrims as defined in claim 1, further comprising, for at least one rim inthe plurality of aluminum alloy rims, determining a weight of thataluminum alloy rim, and wherein dividing the feed of aluminum alloy rimsinto the plurality of batches of aluminum alloy rims comprises, for thataluminum alloy rim, allocating that aluminum alloy rim to the associatedbatch in the plurality of batches of aluminum alloy rims based on boththe composition of that aluminum alloy rim and the weight of thataluminum alloy rim.
 5. The method of recycling aluminum alloy rims asdefined in claim 1, further comprising for each rim in the plurality ofaluminum alloy rims, determining a weight of that aluminum alloy rim,and wherein dividing the feed of aluminum alloy rims into the pluralityof batches of aluminum alloy rims comprises, for each aluminum alloyrim, allocating that aluminum alloy rim to the associated batch in theplurality of batches of aluminum alloy rims based on both thecomposition of that aluminum alloy rim and the weight of that aluminumalloy rim.
 6. A method of recycling aluminum alloy rims, the methodcomprising: providing a feed of a plurality of aluminum alloy rims ofdifferent alloys; for each rim in the feed of aluminum alloy rims,determining a composition of that aluminum alloy rim; determining aplurality of recycled aluminum alloy composition ranges; diving the feedof aluminum alloy rims into a plurality of batches of aluminum alloyrims, each batch of aluminum alloy rims in the plurality of batches ofaluminum alloy rims corresponding to an associated recycled aluminumalloy composition range in the plurality of recycled aluminumcomposition ranges, such that each rim in the plurality of aluminumalloy rims is allocated to an associated batch in the plurality ofbatches of aluminum alloy rims based on the composition of that aluminumalloy rim; for at least one rim in the plurality of aluminum alloy rims,determining a weight of that aluminum alloy rim, where diving the feedof aluminum alloy rims into the plurality of batches of aluminum alloyrims comprises, for that aluminum alloy rim, allocating that aluminumalloy rim to the associated batch in the plurality of batches ofaluminum alloy rims based on both the composition of that aluminum alloyrim and the weight of that aluminum alloy rim; and, for each batch ofaluminum alloy rims in the plurality of aluminum alloy rims,determining, updating and storing batch-specific variables, wherein thebatch-specific variables comprise a batch-specific total weight ofaluminum alloy rims previously allocated to that batch, and abatch-specific average composition of aluminum alloy rims previouslyallocated to that batch, the batch-specific average composition ofaluminum alloy rims previously allocated to that batch is calculatedbased on the weight and the composition of each aluminum alloy rimpreviously allocated to that batch, and for each aluminum alloy rim,allocating that aluminum alloy rim to the associated batch in theplurality of batches of aluminum alloy rims is based on, in addition tothe composition of that aluminum alloy rim and the weight of thataluminum alloy rim, the batch-specific total weight of aluminum alloyrims previously allocated to that batch and the batch-specific averagecomposition of aluminum alloy rims previously allocated to that batch.7. The method as defined in claim 1, further comprising, for each rim inthe plurality of aluminum alloy rims, removing at least a portion of atleast one removable item on that rim.
 8. The method as defined in claim7, wherein the at least one removable item includes at least one of: asteel bushing, a lead balance weight, an extra bolt, a stud, a coating,an anodizing material, and a plating material.
 9. The method ofrecycling aluminum alloy rims as defined in claim 6, wherein determiningthe composition of each aluminum alloy rim is performed by heating amaterial of that rim in at least one spot on a surface of the rim to apoint where the material will emit a characteristic radiation whilecooling down, using a sensor to detect that characteristic radiation,and using a processor to analyze that characteristic radiation todetermine the composition of the material.
 10. The method of recyclingaluminum alloy rims as defined in claim 9, wherein the heating isperformed by focusing a ray of a laser on the at least one spot on thesurface of that rim.
 11. The method of recycling aluminum alloy rims asdefined in claim 9, further comprising exposing a portion of a baremetal surface of the aluminum alloy rim before determining thecomposition of each aluminum alloy rim and wherein the at least one spoton the surface of the rim is located at that portion of the bare metalsurface.
 12. The method of recycling aluminum alloy rims as defined inclaim 6, wherein determining the weight of the aluminum alloy rim for atleast one rim in the plurality of aluminum alloy rims comprises, foreach rim in the plurality of aluminum alloy rims, determining the weightof that aluminum alloy rim, and wherein dividing the feed of aluminumalloy rims into the plurality of batches of aluminum alloy rimscomprises, for each aluminum alloy rim, allocating that aluminum alloyrim to the associated batch in the plurality of batches of aluminumalloy rims based on both the composition of that aluminum alloy rim andthe weight of that aluminum alloy rim.
 13. The method as defined inclaim 6, further comprising, for each rim in the plurality of aluminumalloy rims, removing at least a portion of at least one removable itemon that rim.
 14. The method as defined in claim 13, wherein the at leastone removable item includes at least one of: a steel bushing, a leadbalance weight, an extra bolt, a stud, a coating, an anodizing material,and a plating material.